<?php
/**
 * Class Minify_Build
 * @package Minify
 */

require_once 'Minify/Source.php';

/**
 * Maintain a single last modification time for a group of Minify sources to
 * allow use of far off Expires headers in Minify.
 *
 * <code>
 * // in config file
 * $groupSources = array(
 *   'js' => array('file1.js', 'file2.js')
 *   ,'css' => array('file1.css', 'file2.css', 'file3.css')
 * )
 *
 * // during HTML generation
 * $jsBuild = new Minify_Build($groupSources['js']);
 * $cssBuild = new Minify_Build($groupSources['css']);
 *
 * $script = "<script type='text/javascript' src='"
 *     . $jsBuild->uri('/min.php/js') . "'></script>";
 * $link = "<link rel='stylesheet' type='text/css' href='"
 *     . $cssBuild->uri('/min.php/css') . "'>";
 *
 * // in min.php
 * Minify::serve('Groups', array(
 *   'groups' => $groupSources
 *   ,'setExpires' => (time() + 86400 * 365)
 * ));
 * </code>
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 */
class Minify_Build {

	/**
	 * Last modification time of all files in the build
	 *
	 * @var int
	 */
	public $lastModified = 0;

	/**
	 * String to use as ampersand in uri(). Set this to '&' if
	 * you are not HTML-escaping URIs.
	 *
	 * @var string
	 */
	public static $ampersand = '&amp;';

	/**
	 * Get a time-stamped URI
	 *
	 * <code>
	 * echo $b->uri('/site.js');
	 * // outputs "/site.js?1678242"
	 *
	 * echo $b->uri('/scriptaculous.js?load=effects');
	 * // outputs "/scriptaculous.js?load=effects&amp1678242"
	 * </code>
	 *
	 * @param string $uri
	 * @param boolean $forceAmpersand (default = false) Force the use of ampersand to
	 * append the timestamp to the URI.
	 * @return string
	 */
	public function uri($uri, $forceAmpersand = false) {
		$sep = ($forceAmpersand || strpos($uri, '?') !== false)
		? self::$ampersand
		: '?';
		return "{$uri}{$sep}{$this->lastModified}";
	}

	/**
	 * Create a build object
	 *
	 * @param array $sources array of Minify_Source objects and/or file paths
	 *
	 * @return null
	 */
	public function __construct($sources)
	{
		$max = 0;
		foreach ((array)$sources as $source) {
			if ($source instanceof Minify_Source) {
				$max = max($max, $source->lastModified);
			} elseif (is_string($source)) {
				if (0 === strpos($source, '//')) {
					$source = $_SERVER['DOCUMENT_ROOT'] . substr($source, 1);
				}
				if (is_file($source)) {
					$max = max($max, filemtime($source));
				}
			}
		}
		$this->lastModified = $max;
	}
}
